For some, the mention of the word sends them screaming into the night dreaming of IRQ’s, PCI, HSP, and numerous other acronyms.

For others, it’s a vital lifeline to the internet that one can’t live without.

A little knowledge is a dangerous thing (to misquote someone), but I’m going to try and de-mystify some of the workings of those little green cards that reside in our magic boxes.

Modems come in various flavors, “Hard”, “Soft”, Internal, External, ISA, PCI, AMR, and USB. Don’t worry about what the acronyms mean for now, let’s just concentrate on how they all work.

Think of a modem as a translator who knows two languages; Digital, and Analog. It’s very good at translating the two languages, although it’s better at A-D than D-A. Your phone line is analog, the computer (and modem interface) are digital. The modem (translator) translates the digital data to analog to send it out over the phone line, and translates the analog data to digital so your computer can process it. This happens every time you click your mouse while on the internet. When you click your mouse, you expect something on the screen to change. The modem is getting an analog signal from somewhere, and translating it to digital, processing the data, and thus changing your screen. Of course this is over simplified, but that’s basically all a modem does.

Because of phone line limitations (and government intervention) your modem can send (mouse click) slower than it can receive (change what you see on the screen). It’s limited to 33600 bits per second transmitting, and 53333 bits per second receiving. In an ideal world this is what happens. Slower processors (CPUs), noisy phone lines, multiple A-D conversions, among other things, make this virtually unatainable, and most are lucky to get 28800 bps/48000bps. An analog signal looks like a gentle wave, with peaks and valleys being rounded. A digital signal looks like the parapets on a castle, squared tops and bottoms. The modem must read the wave signal, and determine if the peak is high enough and the valley low enough to translate to digital. A noisy phone line can put false peaks and valleys of noise mixed in with the peaks and valleys of data. This causes the modem to request the same data more than once, and may actually cause a modem to retrain. That is to renegotiate it’s connection to your ISP at a slower rate so it may translate the data better. This is known as throughput. A higher throughput is far more desirable than a higher connect, although the two are linked. In some cases, it may be better to actually slow down the connect speed in order to gain throughput. It gets a little technical, but if you click your mouse, and have to wait 15 to 20 seconds or more before anything happens, you could be suffering from a lack of throughput. Good quality modems will retrain both up and down as line conditions warrant. Cheap soft modems have a much harder time retraining, and usually just hang up.

Now for some terminology:

• “Hard”: A modem that has both a data pump and processing chip on it’s board. These are becoming rare and are mostly ISA slot type.


• “Soft”: A modem that has a data pump, but no processor on it’s board. Also known as “Winmodems” (A term coined by USR/3com), they only work within a Windows environment, and will not work in DOS, or Linux.. These are found in virtually all off the shelf systems today, although I have no idea why a $2500 computer would have a $3 modem in it, it’s just the way it’s done, probably as a cost saving measure.


• “Internal“: A modem that goes inside the box. (duh!). Most internal modems are PCI slot type, and are also soft modems.


• “External“: A modem that doesn’t go inside the box. (duh!). Preferred by most serious modem users, they sit on your desk, have lots of flashing lights, their own power supply, and even more cables to add to the rats nest behind your computer.

There are good and bad modems of all types. I won’t mention chipsets (there are 5 major manufacturers that make all the chips that go on modems), but I will mention what works, and what doesn’t under average conditions. Hard modems are best under all conditions. They will work in virtually all computers from ATs to the latest machines. They are the easiest to set up, the most forgiving of questionable phone lines, and generally preferred overall. Internal or external is a matter of personal preference. Soft modems, under ideal conditions, work as good as hard modems. Of course, ideal conditions are nearly impossible. Good enough for the average surfer, and much cheaper than hard modems. Beware of unknown brands/chipsets, stick with one that you can find easily on the internet, have good support/upgrades available without wading through pages of geekspeak.

• AMR. Audio Modem Riser. Fairly new on the modem scene, these are combination modem/sound on one card, and fit into a special modem riser slot on certain motherboards. Keep away unless your internet connection is second only to how slow you can play solitaire.


• USB. Universal Serial Bus. Also fairly new, and plagued with problems. Flaky motherboard support, and questionable Windows support make these another one to keep away from. If you absolutley know that you have the power to run a USB port with a modem attached, fine, but I’m not recommending these to non-techs. Beware, there are USB soft modems available! Also a little too costly to see any real benefit.

Now that you know just enough to pester your ISP and phone company into helping you get connected, and get connected faster, let’s look at some real world situations. If you live 20 miles from the nearest switching office, buying a new modem isn’t the answer. You will probably never get any faster than 33600bps, so don’t spend $150 on a good hard external modem, you’re wasting money. Better off saving for a house closer to town, or waiting for cable or DSL service. If you live right next door to the switching office, and you still get connects less than 36000bps, there is something else hampering the system. Usually it’s a combination of a cheap soft modem, and very few system resources left. Sometimes just cleaning up the system can dramatically increase connect speeds.. A good hard modem may be a wise purchase.

Good Luck, and Happy Surfing